In the plumbing supply industry many standard items are produced in a range of standard sizes or diameters. More specifically, a line of floor drains may include drains of widely varying diameters in order to suit a wide range of drainage demands. Likewise, waste pipe also is available in a series of diameters (and materials), to meet widely differing needs. However, large diameter floor drains generally are designed to connect to large diameter waste pipes, since this is their most common use. Unfortunately, it is therefore difficult to connect a large diameter drain, when required, to a piping system which uses narrow waste pipe. Although standard reduction coupling members are available, there is often insufficient space available to make use of such devices in the cramped area between ceiling and floor structures. Thus either a smaller, less suitable drain must be specified, or the larger pipe must be run to a point where there is space for the reduction coupler. In either case the resulting plumbing job is less than optimum.